Militants, meanwhile, said they were waiting to see how newly inaugurated President Umaru Yar'Adua would carry out his promises to develop and calm their deeply impoverished region, where the crude in Africa's biggest producer is pumped.

The unknown gunmen hit the same housing estate in the main oil center of Port Harcourt from where several Indians were taken last month, said police spokeswoman Irejua Barasua. Two police officers who responded to the attack were killed in the violence, she said.

She had no details on who was kidnapped. But a human rights activist in the region, who spoke on condition of anonymity due to prohibitions on dealings with the media, said three Asians were taken. Their nationalities weren't known.

Some 200 foreigners have been seized in the restive Niger Delta of Africa's biggest oil producer since militants stepped up attacks in late 2005. Over 100 have been taken this year alone as criminal gangs took up the practice.

Hostages are generally released unharmed after a ransom is paid, although two died in shootouts between hostage takers and security forces. Some 20 foreigners are currently known to be in captivity in the region.

Militants say their kidnappings and bombings of oil infrastructure are meant to force the federal government to earmark greater petroleum funds for their region, which remains desperately poor. They also want the release of two of their leaders, imprisoned on corruption and treason charges.

Yar'Adua called on the militants to lay down arms in his inauguration speech on Tuesday and the militants said they would consider the request.

On Friday, the militants told The Associated Press they weren't likely to immediately end attacks, but were waiting to see how Yar'Adua progresses with a promised dialogue aimed at developing and calming the region a softening of their position toward Nigeria's ex-leader Olusegun Obsanjo, who called them simple criminals.

"There is room for change anyway depending on Yar'adua's actions in the days to come," the spokesman for The Movement for the Emancipation of the Niger Delta, said in an e-mail to the AP.

That group is holding six foreigners taken May 1 and had earlier said the group would be released Thursday, but they remained in captivity. The militants said security concerns had delayed the handover, but that it could come on Friday.